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CMYK Halftone Effect with empy dots
Posted: 2019-02-13T04:53:29-07:00
by myspacee
Hello,
fascinating by this :
https://imgur.com/gallery/4mux7bJ
i'm asking how they made CMYK painting by hand. I think they are cheating.
Is possibile to use IM to 'convert' an image to CMYK Halftone Effect but where dots are empty ?
(only edge of a circles are considered)
In this way i can print the image on canvas using a normal in-store printing technique,
then pass by hand every dots respecting CMYK sequence.
Thank you for reading,
m.
Re: CMYK Halftone Effect with empy dots
Posted: 2019-02-13T10:36:22-07:00
by myspacee
Hello,
found something related in this old post :
http://www.imagemagick.org/discourse-se ... 754#p70754
But i'm not able to adapt old Linux syntax to last windows IM build.
Can you help me ?
thank you,
m.
Re: CMYK Halftone Effect with empy dots
Posted: 2019-02-13T10:43:25-07:00
by fmw42
see
https://imagemagick.org/Usage/windows/
remove the \ from the \( ... \)
change the end of line \ to ^
Re: CMYK Halftone Effect with empy dots
Posted: 2019-02-13T12:13:37-07:00
by myspacee
Thank you for reply fmw42,
can't solve all issue (and my limits).
In 2010 you reply
https://www.imagemagick.org/discourse-s ... =1&t=17389 to user that ask how create B/W Halftone Dither.
The result is similar to goal i want reach :
In above image the dots are exactly what i want (missing negative effect).
I don't know if the right way is to split image to 4 CMYK greyscale files, then treat them like b/w image, apply B/W Halftone Dither
giving the angles of the offset printing halftone and at least rejoin.
As idea, can works ?
(I'm fascinated by the idea of turning an computer image into a real object)
Thank you for your time,
m.
Re: CMYK Halftone Effect with empy dots
Posted: 2019-02-13T13:09:41-07:00
by myspacee
Hello again sorry for hammering.
Find CNC software that does exactly what i need
http://jasondorie.com/page_cnc.html
You can apply also angle to emulate four color and then join them.
Program take an image and create BIG b/w images composed by dots.
If possibile, can you post command to :
- change black dots color into Ciano, Magenta, Yellow.
- 'reduce' the intensity (TINT) of the dots color
- create PNG with white as trasparent color
- command to join 4 files back
Thank you,
m.
Re: CMYK Halftone Effect with empy dots
Posted: 2019-02-13T13:43:58-07:00
by snibgo
See the examples at
http://www.imagemagick.org/Usage/quanti ... red-dither , also my own
Lithographic effects.
We can separate a CMYK image, apply an angled dither to each image, and re-combine. (We do the "angled dither" by rotating the image, dithering, then rotating back.) Windows BAT syntax:
Code: Select all
set OD=-ordered-dither c7x7w
%IMG7%magick ^
toes.png ^
-colorspace CMYK ^
-channel CMYK ^
-separate ^
+adjoin ^
odc-%%d.miff
%IMG7%magick ^
odc-0.miff ^
+distort SRT 1,15 ^
%OD% ^
+distort SRT 1,-15 ^
-crop 267x233+0+0 ^
+repage ^
odc-out0.miff
%IMG7%magick ^
odc-1.miff ^
+distort SRT 1,75 ^
%OD% ^
+distort SRT 1,-75 ^
-crop 267x233+0+0 ^
+repage ^
odc-out1.miff
%IMG7%magick ^
odc-2.miff ^
%OD% ^
odc-out2.miff
%IMG7%magick ^
odc-3.miff ^
+distort SRT 1,45 ^
%OD% ^
+distort SRT 1,-45 ^
-crop 267x233+0+0 ^
+repage ^
odc-out3.miff
%IMG7%magick ^
odc-out0.miff odc-out1.miff odc-out2.miff odc-out3.miff ^
-set colorspace CMYK ^
-combine ^
-colorspace sRGB ^
cmyk_dith.png
Re: CMYK Halftone Effect with empy dots
Posted: 2019-02-13T15:59:04-07:00
by fmw42
I thought my instructions above were pretty simple to follow. Nevertheless, here is the Unix to Windows syntax conversion.
- remove the \ from the \( ... \)
- change the end of line \ to ^
Here is the Unix syntax:
Code: Select all
convert birdofparadise.gif -level 0x70% \
-set option:distort:viewport '%wx%h+0+0' \
-colorspace CMYK -separate null: \
\( -size 2x2 xc: \( +clone -negate \) \
+append \( +clone -negate \) -append \) \
-virtual-pixel tile -filter gaussian \
\( +clone -distort SRT 60 \) +swap \
\( +clone -distort SRT 30 \) +swap \
\( +clone -distort SRT 45 \) +swap \
\( +clone -distort SRT 0 \) +swap +delete \
-compose Overlay -layers composite \
-set colorspace CMYK -combine -colorspace RGB \
birdofparadise_cmyk_halftone_2.png
Code: Select all
convert birdofparadise.gif -level 0x70% \
-set option:distort:viewport '%wx%h+0+0' \
-colorspace CMYK -separate null: \
\( -size 3x3 xc: \( +clone -negate \) \
+append \( +clone -negate \) -append \) \
-virtual-pixel tile -filter gaussian \
\( +clone -distort SRT 60 \) +swap \
\( +clone -distort SRT 30 \) +swap \
\( +clone -distort SRT 45 \) +swap \
\( +clone -distort SRT 0 \) +swap +delete \
-compose Overlay -layers composite \
-set colorspace CMYK -combine -colorspace RGB \
birdofparadise_cmyk_halftone_3.png
Here is the Windows syntax:
Code: Select all
convert birdofparadise.gif -level 0x70% ^
-set option:distort:viewport '%wx%h+0+0' ^
-colorspace CMYK -separate null: ^
( -size 2x2 xc: ( +clone -negate ) ^
+append ( +clone -negate ) -append ) ^
-virtual-pixel tile -filter gaussian ^
( +clone -distort SRT 60 ) +swap ^
( +clone -distort SRT 30 ) +swap ^
( +clone -distort SRT 45 ) +swap ^
( +clone -distort SRT 0 ) +swap +delete ^
-compose Overlay -layers composite ^
-set colorspace CMYK -combine -colorspace RGB ^
birdofparadise_cmyk_halftone_2.png
Code: Select all
convert birdofparadise.gif -level 0x70% ^
-set option:distort:viewport '%wx%h+0+0' ^
-colorspace CMYK -separate null: ^
( -size 3x3 xc: ( +clone -negate ) ^
+append ( +clone -negate ) -append ) ^
-virtual-pixel tile -filter gaussian ^
( +clone -distort SRT 60 ) +swap ^
( +clone -distort SRT 30 ) +swap ^
( +clone -distort SRT 45 ) +swap ^
( +clone -distort SRT 0 ) +swap +delete ^
-compose Overlay -layers composite ^
-set colorspace CMYK -combine -colorspace RGB ^
birdofparadise_cmyk_halftone_3.png
If in a bat file, double the % to %%
I have brightened them by adding -level 0x70%
Re: CMYK Halftone Effect with empy dots
Posted: 2019-02-13T17:27:39-07:00
by fmw42
Here is perhaps a better one, by making the K channel all black.
Code: Select all
convert birdofparadise.gif \
-set option:distort:viewport '%wx%h+0+0' \
-colorspace CMYK -separate null: \
\( -size 3x3 xc: \( +clone -negate \) \
+append \( +clone -negate \) -append \) \
-virtual-pixel tile -filter gaussian \
\( +clone -distort SRT 60 \) +swap \
\( +clone -distort SRT 30 \) +swap \
\( +clone -distort SRT 45 \) +swap \
\( +clone -fill black -colorize 100 -distort SRT 0 \) +swap +delete \
-compose Overlay -layers composite \
-set colorspace CMYK -combine -colorspace RGB \
birdofparadise_cmyk_halftone_3b.png
Re: CMYK Halftone Effect with empy dots
Posted: 2019-02-14T03:36:13-07:00
by myspacee
snibgo, fmw42,
thank you both.
Different solutions and I need some tuning to go on print on 'real thing', but it's incredible.
Thank you again,
m.